The present invention relates generally to printing plate clamping assemblies known colloquially in this art, and referred to as such below, as xe2x80x9clock-upxe2x80x9d assemblies. In especially preferred forms, the present invention is embodied in printing plate lock-up assemblies which may adjustably accommodate different print plate widths (i.e., so as to allow printing onto different web widths).
It is increasingly becoming a necessity for newspaper and magazine publishers to be capable of accommodating narrower width paper webs. For example, many newspaper publishers have decided to reduce the newspaper width so as to conserve newsprint. At the same time, however, such publishers may from time to time have a need to utilize their printing presses in order to print publications on paper webs having a wider width as compared to the narrower width of the newsprint that is desired to be employed. While a variety of lock-up devices have been proposed in the past (see, for example, U.S. Pat. No. 4,191,106 to Fermi et al, U.S. Pat. No. 5,186,108 to Hillebrand and U.S. Pat. No. 5,327,832 to Fischer, the entire content of each being expressly incorporated hereinto by reference) to allow for print plates of different widths to be used on a given print plate cylinder (and thereby allow for different web to be printed), some further improvements are still desired.
For example, it would be highly desirable if a lock-up assembly could be provided with a registration pin that is laterally (i.e., along the longitudinal axis of the printing press and thus in the width-wise dimension of the printing plate carried thereby) shiftable between one and another positions (i.e., so as to accommodate different printing plate widths) without necessarily moving the lateral position of the lock-up jaws. Furthermore, it would be highly desirable if the lock-up jaws were capable of being shifted laterally in a convenient manner so as to also be capable of accommodating different printing plate widths. It is towards providing such lock-up assemblies that the present invention is directed.
Broadly, the present invention is embodied in lock-up assemblies so as to clamp a flexible print plate to a circumferential surface of the print plate cylinder. In especially preferred embodiments, the print plate Lock-up assemblies of the present invention are adapted to being received within a gutter of a print plate cylinder and include an elongate support bar assembly, and a jaw assembly supported by the support bar assembly and adapted for positionally clamping a print plate to an exterior circumferential surface of the print plate cylinder.
Preferably, the jaw assemblies include a pair of retainer blocks which are spaced from one another along the support bar assembly, and a jaw support plate positioned between the pair of retainer blocks and adapted for movement along the pair of retainer blocks towards and away from the support bar. A pair of mirror-imaged jaw members is positioned upon and supported by said jaw support plate. One or more spring members act between the support bar assembly and the jaw support plate so as to exert a bias force against the jaw support plate to thereby move the jaw support plate, and the pair of jaw members supported thereby, in a direction away from said support bar assembly. In such a manner, the jaw members may be moved into clamping relationship with the print plate gutter.
The lock-up assemblies of the present invention also most preferably include a registration pin assembly which may be shiftable between one and another locations along the support bar assembly. Most preferably, the registration pin assembly is positioned between a pair of the jaw assemblies as noted above and includes a pin cradle supported which is shiftable along the support bar assembly, and defines a slot oriented generally transverse to the support bar assembly (and to the gutter). A registration pin is received within the slot of the pin cradle and defines a threaded bore. A threaded jack screw is threadably received within such threaded bore of the registration pin so that a terminal end thereof bears against the pin cradle. When turning movements are therefore applied to the jack screw, the registration pin will responsively be raised or lowered relative to said pin cradle. In this manner, the registration pin may be brought into and out of positive locking engagement with the plate cylinder gutter.
According to yet another aspect of this invention, gauge systems and methods are provided to ensure accurate placement within an elongate print cylinder gutter of a registration pin assembly having a pin cradle which is shiftable between one and another locations within the gutter, a registration pin oriented substantially transverse to the gutter, and a jack screw received within a threaded bore of the registration pin and such that a terminal end thereof bears against the pin cradle to responsively cause the registration pin to be jacked into and out of engagement with the cylinder gutter. More specifically, the gauge system includes a gauge bar positioned on an exterior surface of the print plate cylinder and having at least one elongate window through which the registration pin assembly is accessible, and first and second stops separated from one another along the elongate window which establish the one and another locations of the registration pin assembly. A gauge block may be placed over the elongate window of the gauge bar and has a base plate adapted for slidable movement along the gauge bar between such first and second stops. A finger block is provided with the gauge block which is engageable with the registration pin. A through bore in registry with the jack screw of the registration pin assembly is formed in the gauge block.
A turning tool may therefore be inserted into said through bore so as to engage with said jack screw and allow turning movements to be applied thereto. In such a manner, turning movements applied in one direction causes the registration pin to be jacked away from positive locking engagement with the gutter to allow for the registration pin assembly and the gauge block to be slideably moved as a unit between the first and second stops of said gauge bar to thereby shift said registration pin assembly from one location to said another location thereof, respectively. By applying turning movement in another direction upon the registration pin assembly being positioned at another location, the registration pin will then be jacked into positive engagement with the cylinder gutter to thereby positionally retain the registration pin assembly at that another location.
These and other aspects and advantages will become more apparent after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.